Colorado Hazard and Flood Mapping Resources Portal
A Service of the Colorado Water Conservation Board
The Colorado Hazard and Flood Mapping Resource Portal is a one-stop shop for flood risk information. The Colorado Water Conservation Board compiled these resources to help those in Colorado prepare for and recover from major flood events. CWCB helps with:
- Coordination of federal, state and local resources;
- Dissemination of flood-related information;
- Documentation of flood damages and flooded areas;
- Mapping and remapping of regulatory flood prone boundaries based on the best information and technology; and
- Technical guidance and financial support to communities.
The Colorado Water Conservation Board’s mission is to conserve, develop, protect and manage Colorado’s water for present and future generations. It works to make communities across Colorado safer and more resilient to flooding.
CWCB as a FEMA Cooperating Technical Partner
The CWCB has been a FEMA Cooperating Technical Partner (CTP) since July 15, 2002. Projects include:
- State-wide LiDAR acquisition.
- Base Level Engineering development initiated for 40 of 62 counties (with intent to cover all counties).
- Risk MAP projects initiated in 40 of 62 counties (with intent to cover all counties).
- Colorado Hazard Mapping Program (CHAMP).
- Letter of Map Revision Review Partners delegation; state-led special projects to advance science, technology, and communications.
About the Colorado Floodplain Mapping Program
After the 2013 flooding in Colorado, there were major changes to floodplains and flood risk. Colorado's legislature passed SB 15-245: Provide State Funding To Map Natural Hazard Areas to reanalyze potential hazards; this included flooding for streams that were affected by the 2013 flood event. The bill sought to provide a mitigation and land use framework in areas likely to be affected by future flooding, erosion, and debris flow events. The state determined that updated risk information was needed to inform rebuilding efforts. This way, homes, businesses and infrastructure could be rebuilt safely. Communities also needed to prioritize funding towards rebuilding.
The Colorado Hazard Mapping Program (CHAMP) was set up; its vision was to help communities become more resilient through comprehensive mapping of floodplains and other natural hazards. FEMA would use the results from CHAMP in Risk Mapping, Assessment and Planning (Risk MAP).
Specifically, they would be used to update Flood Insurance Rate Maps (FIRMs) for affected communities. CWCB's Floodplain Mapping Program has since worked with FEMA through Colorado Risk MAP to expand our initiative for updated flood risk mapping and other natural hazard awareness across the state.
CWCB currently has ongoing studies in most of Colorado. These can be publicly accessed at the Colorado Hazard Mapping & Risk MAP Portal website :
Colorado Hazard Mapping & Risk MAP Portal - CO Hazard Mapping & Risk MAP Portal
The Colorado Hazard Mapping & Risk MAP Portal is a website that CWCB hosts to display mapping results from various efforts to give community representatives, consultant engineers and the public access to information on flood risk. From simple definitions to technical data to training videos, the portal is a one-stop shop for flood risk information. It also has detailed information for projects across the state.
The landing page helps guide the user to other pages based on what they are looking for.
Flood Hazard Page
The Flood Hazard page is a portal to several helpful items for users. This page has most of the information on flood risk in Colorado that people need to see. This includes flood risk information for a specific property; countywide data; general information about flood hazards; or information about the initial Colorado Hazard Mapping Program (CHAMP) floodplain mapping study which resulted in the mapping products now available on the website.
The Homeowner Tool
Homeowners or business owners can enter their address to receive a customized report of the flood hazards for their property. This is mainly for areas with ongoing flood studies; property owners can view the changes from the proposed maps to the effective ones. However, the tool works for any property in the state.
Homeowner Report
After entering an address, a Homeowner Report is generated; it can be saved locally as a PDF document. The report includes the currently identified, or effective, flood risk as shown on the FIRM. The report also includes newly identified flood risks associated with studies that are not yet effective (i.e. draft and Preliminary phases).
Other flood information can be found at the bottom of the report to help property owners better assess their risk. This includes depth of flooding, water surface elevation, percent chance of flooding each year, and more. This information is given at a single point as identified on the map.
Flood Information by County
CWCB has partnered with FEMA to bring updated flood risk information to the state.
Flood risk projects are mainly done on a countywide basis. This section of the website shows you which Risk MAP projects are currently happening in a given county. This data can be found by clicking on the county name.
The information provided for each county includes summaries of ongoing projects; project schedules and milestones; materials from all outreach efforts to date; floodplain mapping data; and technical information including mapping Changes Cince Last FIRM (CSLF) and depth and water surface elevation grids. This technical information helps users understand how the flood risk has changed with their FIRM update and how deep floodwaters can be in those areas.
The data can be found by scrolling through the county-specific tabs at the top of the page. Users can also click specific sections in the header ribbon. Users can zoom in and out on the map and click features for more information. Consistent layout and terminology for each county makes the website easy to learn for new users. It also lets users find information quickly.
All pertinent information from ongoing and past projects in the county can be found on this page.
Floodplain Mapping
The floodplain mapping tab is one of the key sections for home and business owners. Preliminary Floodplains is checked by default. This lets users see preliminary or draft results from ongoing flood studies.
Users can uncheck Preliminary Floodplains and check the National Flood Hazard Layer (NFHL) Flood Hazard Zones to see the effective FIRM information that is used for floodplain management, regulation of development, and insurance rating.
The National Flood Hazard Layer effective data can be shown even if there is no ongoing study; this information needs to be available digitally to be displayed. The effective information will be revised once the preliminary data has been adopted.
Changes Since Last FIRM (CSLF)
The CSLF section compares the preliminary and effective data. It shows where floodplains will likely be larger or smaller based on the updated analysis. This lets homeowners see the differences between the ongoing study results and the effective information.
By default, the 1%-annual-chance floodplain changes are shown; this is the flood hazard information used for regulatory purposes.
Users can also turn on floodway changes to see if and where floodways are changing. Floodways are areas of the floodplain that have more strict building requirements; they are subject to the same insurance requirements as the 1%-annual-chance area.
Turning on the 0.2%-annual-chance option lets users see the area used by some communities to regulate critical facilities such as hospitals, schools, and fire stations. The National Flood Hazard Layer can also be turned on to see effective information.
Depth Grids
The Depth Grids section shows the expected depths of flooding based on preliminary data.
Clicking on a location will estimate the depth of flooding during a 1%-annual-chance flood event. This box will stay active and will update based on any other tabs clicked.
Percent Annual and Other Data
Typically, Flood Insurance Rate Maps (FIRM) indicate areas where there is a 1% and .2% annual chance of flood in any given year. The Colorado Water County Board has completed studies that show where floods may occur at a greater interval than 1% to show where there is greater risk of flooding in any given year. Other percent-annual-chance flood scenarios can help understand the potential impacts of other flood events and better inform the community of their risk. In the Percent Annual section, users can see the chance of flooding at any given location in any given year. Clicking on a point in the map will show the likely chance of flooding at that location – the higher the percentage, the higher the risk.
Other sections include: velocity grids; 30% grids; water surface elevation grids; hydraulic modeling information; hydrology information; survey locations; and LiDAR datasets used for the study.
Light Detection and Ranging (LiDAR) Download Portal
CWCB, in partnership with other agencies, started acquiring Quality Level 2 LiDAR data in 2010. LiDAR is high quality ground elevation data. The goal is to obtain coverage for the whole state. Complete coverage is expected by the end of 2022.
The LiDAR Download Portal is a page on the CWCB website to locate and download topographic data. The webpage provides easy access for anyone looking for the latest LiDAR products.
Users can zoom in on the map and select tiles for their area of interest. They can select specific LiDAR data or tiles in the table after expanding a specific dataset location. They can also draw an area directly on the map. As tiles are selected, the “LiDAR Request Form” in the bottom of the sidebar will show how many tiles are selected, available formats and the file size. Users can download the files directly without involving CWCB staff.
Colorado Letter of Map Revision Review Program
CWCB added the Letter of Map Revision (LOMR) Review Partners Program in 2021. This program processes Colorado MT-2 map revision requests outside the Denver metro area on FEMA’s behalf.
CWCB works with engineering firms to perform technical review. The review program coordinates with FEMA, FEMA’s Production and Technical Services contractor, and the Mile High Flood District (Cooperating Technical Partner for the Denver metro area) to provide MT-2 processing across the state.
Several resources about the LOMR Review Program, including conditional letter requests, are available on the Colorado Hazard Mapping & Risk MAP Portal hosted by the CWCB website . A clear step-by-step process with links to documents and templates helps to clarify the map revision process. Frequently Asked Questions and flow charts also help to address common questions.
Notable Projects
CWCB is aware of the dynamic and evolving field of floodplain management. CWCB strives to maintain its status as a leader in the industry by leading notable projects. These keep the region at the forefront of advancements in the industry.
The following notable projects are just some of the CWCB-led efforts that were recently finished or are underway:
- Statewide climate scaling for future conditions.
- Effective project reaches and models visual tracker.
- Mitigation technical assistance pilot.
- Communications tracker.
- LiDAR Letter of Map Amendment submittal how-to guide.
- Point contributor time estimator.
- Multi hazard mapping.
- Ice jam analysis.
- Post fire analysis.
- State-funded hydrology updates for the Arkansas, Yampa, Colorado and Rio Grande rivers.
Planning Tools for Local Officials and Mapping Partners
The website also has information that is available to CWCB's mapping partners. A status dashboard lets the team see the status of all projects in one location. An administration section lets each team member upload files so updates do not have to go through one person. The information in this section of the website helps support local planning and prioritization. If you have any questions about any of these tools or resources reach out to CWCB for information.
Prioritization Tool
The Prioritization Tool is a map of Colorado counties. It has information to help decide where flood risk projects are needed and what they should focus on. Users can toggle between data categories like population or structures at risk. They can then modify the options to compare results on a county by county basis. This tool helps to develop and update CWCB’s five-year Work Plan.
Community-Tailored Products
The planning tools section of the website also has a contractor checklist. This is a collection of all the materials common to each flood risk project. It includes meeting agendas, presentation templates, fact sheets for communities, property owner notification templates, and other documents used to send information throughout the life of a project. The content is grouped into project phases and steps. This lets users access the materials quickly. It also ensures consistency among the contractors working on flood risk projects for CWCB.
A key subset of information is the Discovery Packet. This presents clear and direct materials that are tailored to meeting participants in each community. Items in the packet include a community discovery dashboard that summarizes tasks and schedules; a community outreach checklist that defines the community’s role in each step of Risk MAP; a discovery questionnaire that asks participants for feedback; step-by-step instructions on how to work with the digital map package deliverable; and more.
CTP Overview
CWCB has been a CTP since July 15, 2002. Participation in the CTP program allows Colorado to leverage state funding to provide an immeasurable benefit to the citizens of Colorado in the form of improved outreach, closer relationships, increased understanding of local conditions and circumstances that may affect floodplain mapping and other aspects of flood hazard reduction.
CWCB staff in all areas routinely visit and interact with citizens in all regions within the state, and this promotes an awareness of the factors that affect flood hazards. These partnerships result in an enhanced ability to deliver flood hazard information and assist communities to arrive at mitigation techniques to reduce hazards.
CWCB appreciates the opportunity offered by FEMA over the last twenty years to take a direct role in the solution of natural hazard management on behalf of the citizens of the State of Colorado.
